考虑一个条目,其条目仅由-1或1组成.如何获得仅包含1且最小长度为t的所有切片的范围(例如t = 3)
例：
>>>a=np.array([-1,-1,1,1],dtype=int)
>>> a
array([-1,1])
然后,期望输出fort = 3将是[(2,7),(11,15)].
最佳答案
使用
np.diff和np.where的一种方法 –
# Append with `-1s` at either ends and get the differentiation
dfa = np.diff(np.hstack((-1,a,-1)))
# Get the positions of starts and stops of 1s in `a`
starts = np.where(dfa==2)[0]
stops = np.where(dfa==-2)[0]
# Get valid mask for pairs from starts and stops being of at least 3 in length
valid_mask = (stops - starts) >= 3
# Finally collect the valid pairs as the output
out = np.column_stack((starts,stops))[valid_mask].tolist()